This application is related to and claims priority from Japanese Patent Application No. 2001-8165 filed on Jan. 16, 2001, the contents of which are hereby incorporated by reference.
The present invention relates to a cooling device for cooling a heat-generating element by movement of latent heat based on boiling and condensation of refrigerant.
In order to cool elements for an electronic unit such as computer chips, air-cooling fins made of aluminum and the like have frequently used. However, since the heat-generating amount has been increasing year after year with improvement in performance of those elements, the air-cooling fins have become difficult to cope with them.
Thus, there has been developed a cooling device which transmits heat of those elements to refrigerant to cool those elements by means of movement of latent heat based on the boiling and condensation of the refrigerant.
An example of a cooling device using the refrigerant has been disclosed in, for example, Japanese Patent Application Laid-Open No.10-308486. The cooling device disclosed in this official gazette includes, as shown in FIG. 7, a refrigerant container 100 constructed by stacking a plurality of sheets of plates, and radiating fins 110 mounted to the refrigerant container 100 so as to contact a radiating surface thereof.
The above-described cooling device is capable of coping with various cooling capacity by increasing or decreasing a number of sheets of the plates constituting the refrigerant container 100 to thereby change the height of the refrigerant container 100. However, since the surface area of the plates is constant, it is difficult to change the shape of the radiating fins 110 extensively even if the capacity of the refrigerant container 100 is changed. More specifically, in the radiating fins 110 shown in FIG. 7, an extrusion production of aluminum is generally used. Accordingly, in order to change the shape of the radiating fins 110, the need for designing a new extrusion die arises, resulting in very high cost.
Although it is comparatively easy to change the height of the refrigerant container 100, when the heat receiving area and the radiating area are greatly changed according to the number of heat-generating elements 120 or the heat-generating amount thereof, the need for changing the basic size of the plates arises. Therefore, expense required for a press die for manufacturing the plates will become expensive.
As another example of the previously known cooling devices, there is also known a cooling device 500, as shown in FIG. 26, that includes a refrigerant container 510, and a radiating core portion 520 having tubes 540 connected to the refrigerant container 510 and a header tank 560 connected to the other side ends of the tubes 540. The refrigerant container 510 and the header tank 560 are constructed of plural sheets of stacked plates, and are connected by inserting a member into apertures formed in the plates.
In the cooling device 500, a balance between refrigerant-side cooling capability to be adjusted by pressure loss of refrigerant passing through each tube 540, and air-side cooling capability to be adjusted by flow resistance of air passing through a radiating core portion 520 is set, so that the radiating capability of the cooling device 500 is adjusted. As one of means for adjusting the pressure loss of the refrigerant and the air-flowing resistance, an interval of the tubes 540 can be changed. However, in order to change the interval of the tube 540, it is necessary to change also the number of apertures in the plates, into which tubes 540 are to be inserted. For this reason, expense required for a press die for manufacturing the plates becomes expensive with the number change of apertures in the plates.
Further, in the cooling device 500, if the refrigerating container 510 and the header tank 560 are made to be close to each other or if the interval of the tubes 540 is narrow, it is difficult to insert the assembling jig. Particularly, in order to assemble the tube 540 positioned at the central part of the radiating core portion 520, a complicated operation will be needed.
The present invention has been achieved in view of the above-described problems, and is aimed to provide a cooling device capable of changing the size easily and at low cost in accordance with necessary cooling capacity.
In a cooling device according to the present invention, plural unit plates having the same shape are stacked in a plate-thickness direction, and are sandwiched between the two outer plates. On the surface of one outer plate among the two outer plates, radiating fins having the substantially same width as the unit plate are disposed. When refrigerant vapor boiled and vaporized by heat from a heat-generating element flows in slits provided on each unit plate, heat of the refrigerant vapor is radiated from the one outer plate to the outside through the radiating fins. Relative to the two outer plates, two or more sheets of the unit plates are arranged in parallel. Further, with respect to one outer plate, radiating fins are arranged in parallel by the number corresponding to the unit plates arranged in parallel.
According to this structure, it is possible to readily increase or decrease the number of the unit plates arranged in parallel relative to the outer plates, and the number of the radiating fins, in accordance with the necessary cooling capacity. Even when the size of the cooling device changes, common components can be used without the need for changing the shape of the unit plate and radiating fins. Therefore, it is possible to greatly reduce the component manufacturing cost, and to easily change the size of the cooling device.
Preferably, the size of the header is changed in accordance with the number of the unit plates arranged in parallel on the two sheets of outer plates. For this reason, it is possible to easily secure necessary cooling performance.
The cooling device includes a boiling unit for storing therein liquid refrigerant, and a condensation unit for condensing refrigerant vapor boiled and vaporized in the boiling unit. The heat-generating member is attached on a surface of the boiling unit. The condensation unit is constructed by stacking plural sheets of the unit plates between the two sheets of the outer plates, and the boiling unit and the condensation unit are coupled together through a pipe. Accordingly, it is easy to change the size of the condensation unit, and it is possible to easily change the radiating performance by the change of the size. Since the boiling unit and the condensation unit are coupled together through the pipe, it is also possible to change the radiating performance by changing the number of pipes.
A cooling device according to the present invention includes a plurality of tubes inside which refrigerant passes, a refrigerant container in which refrigerant is sealed, and a header tank. The heat-generating element is mounted on a surface of the refrigerant container, and one side ends of the tubes communicates with the refrigerant container. The other side ends of the tubes are connected to the header tank to be communicated with each other. In this cooling device, refrigerant within the refrigerant container is boiled and vaporized by the heat from the heat-generating element, and flows into the tubes to perform heat-exchange with the outside air. A core unit has a tube group consisting of the tubes arranged in parallel, and unit plates in which both side ends of the tube group are inserted respectively. Here, each of the unit plates is suitable for the size of each tube group. In the cooling device, a plurality of the core units are arranged in accordance with a necessary cooling capacity.
According to this structure, the number of the core units is changed or core units having different cooling performance are combined, so that it is possible to easily adjust the cooling performance. Since the tubes constituting each core plate are arranged in parallel, it is easy to insert a jig between both tubes, and there is no need for any complicated assembling operation. Particularly, according to the present invention, the plural core units in which the tubes are installed to the unit plates are arranged to construct the cooling device. Therefore, no complicated operation is needed to install the tube at the central part of the cooling device even if the tube interval is narrow or plural core units having different tube intervals are combined.
Preferably, the tube at the outermost side in the tube group in a tube-laminating direction, has an insert to be inserted into the unit plate. For this reason, it is possible to fix the unit plate and the unit plate by the insert, and to prevent the tubes from being removed during transportation and others.
Among the flat plate members, a flat plate member arranged on the outermost side has a pawl, and the plural flat plate members are fixed by the pawl. Thereby, plural sheets of plates stacked in order to constitute the refrigerant container or the header tank can be fixed by using the pawl.
Each of the fins has a plate-like base portion extending in an air-flowing direction, and a wall portion bent from the base portion which abuts against the wall surfaces of the tubes. In addition, the fins are stacked in a tube-longitudinal direction. By inserting the fins in the air-flowing direction, the fins can be readily installed between the tubes and there is no need for any complicated operation.